Observations on the reproduction of Pugilina morio (Linnaeus, 1758) (Mollusca : Gastropoda : Melongenidae)

3 Pages·2003·1.6 MB·English

by  I X Martins

THE VELIGER
© CMS, Inc., 2003
The Veliger46(3):267-274 (July 1, 2003)
NOTES, INFORMATION & NEWS
Observations on the Reproduction of ing, 10 capsules were observed daily, and the stage of
Pugilina morio (Linnaeus, 1758) development of most individuals was recorded.
(Mollusca: Gastropoda: Melongenidae) To determine the spawning season, monthly field ob-
servations were made from January 1998 to December
Helena Matthews-Cascon 1999 in the estuary of the Ceara River.
Departamento de Biologia, Centre de Ciencias, Results
Universidade Federal do Ceara, Campus do Pici,
60455-970, Fortaleza, Ceara, Brazil; [email protected] The reproductive period ofPugilina morio in the estuary
of the Ceara River during both years, 1998 and 1999,
lasted from July to November with a peak in September.
Ines Xavier Martins
In the field, P. Morio spawned egg masses on rocks or
on the pilings from the old harbor. In the laboratory, the
Centro de Ciencias da Saiide, Universidade de Fortaleza
egg masses were attached to the surface ofthe aquarium.
(UNIFOR), Av. Washington Soares, 1321, Edson
— — The egg masses were beige when released and later be-
Queiroz, Fortaleza Ceara Brazil; [email protected]
came yellow.
and mm
The capsules measured 10-15 in length (mean
Evelyne Ximenes Barbosa 13.3 mm ± SD 0.98, n = 116) and 8-14 mm in width
(mean 11.8 mm ± SD 1.00, n = 116) (Figures 2, 3), and
Departamento de Biologia, Centro de Ciencias, each capsule contained 50-167 eggs (mean 97.4 ± SD
Universidade Federal do Ceara, Campus do Pici, 43.2, n = 116). The Pugilina morio capsules have five to
60455-970, Fortaleza, Ceara, Brazil
six ridges on the side with the exit aperture, and are
The family Melongenidae is represented in Brazil only smooth on the side opposite the exit aperture. Each cap-
by the species Pugilina morio (Linnaeus, 1758) (Mat- sule has an exit plug located laterally on the upper side
thews, 1967; Rios, 1994) (Figure 1) which is very com- of the capsule as illustrated in Figure 2. The plug cov-
mon in estuarine areas. Pugilina morio is a slow moving ering this exit aperture was opaqmume with an elliptical
predator that preys mainly on bivalves using the foot to shape, measuring between 0.8-2.5 in diameter (mean
embrace the prey, putting the outer lip of the shell be- 1.6 mm ± SD 0.40, n = 94).
tween the valves, and then introducing the pleurembolic The trochophore stage was reached by day 16 and the
proboscis (Matthews-Cascon et al., 1990). This species early veliger stage by day 30. Hatching as late stage ve-
has a sexually dimorphic shell, with the females having ligers larvae occurred between 7 to 8 weeks after ovi-
a larger body whorl than the males (Matthews-Cascon et position.
al., 1990). Some human populations use Pugilina morio The veliger larva has a large velum with four lobes,
as a food source. with two lines of cilia on the edge of the velum. The
In the present study the following aspects of Pugilina protoconch has two whorls and is light brown in color
morio spawn were studied: size of the egg capsules de- (Figure 4). The first whorl has a granular appearance
posited per female, number of eggs per capsule, and the (Figure 5). The second whorl is clearly distinct from the
length of the development period. first whorl and exhibits a series ofridges crossed by weak
In July of 1998, 56 egg capsules and 30 adults ofPug- growth lines (Figure 6). The protoconch measures be-
ilina morio (20 females, 10 males) were collected in the tween 700 and 750 [xm (mean 722 ± SD 24.9 |xm, n =
estuary of the Ceara River, Fortaleza, Ceara, Brazil 10) (Figures 7, 8).
(0.38°35'15"W; 0.3°41'54"S) and transferred to the labo- After hatching from the egg capsule at the late veliger
ratory where they were kept in well aerated 60 literwater stage, already with the foot, the larvae remained swim-
tanks at a constant temperature (28°C) and salinity (30%o) ming around the capsule for 24 hours and then started
and fed ad libitum during 3 months. crawling in the tank bottom, already with the velum re-
We measured length and width of egg capsules and absorbed. Nurse eggs were not observed, and 90% of all
counted the number of eggs in each for 60 capsules laid the embryos hatched. The other 10% did not develop and
in the tanks by the 20 females and 56 collected in the remained untouched in the egg capsule.
field. To determine the duration of the intracapsular After the apical plug opened, the egg masses were at-
trochophore and veliger stages and the period until hatch- tacked by protozoans and nematodes that ate the rest of
Page 268 The Veliger, Vol. 46, No. 3
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Figures 1-8. Piigilina inorio. Figure 1. Female spawning. Figure 2. Egg capsules, 12 mm in lengtli and 9 mm in width. Figure 3. Egg
masses. Figure 4. SEM dorsal view ofthe protoconch. Figure 5. SEM detail ofthe first whorl ofthe protoconch. Figure 6. SEM. detail
of the second whorl of the protoconch. Figure 7. SEM, ventral view ofthe protoconch. Figure 8. SEM, detail ofthe apertural view of
the protoconch.
Notes, Information & News Page 269
the material that remained inside the capsules. Some egg Matthews-Cascon, H., H. R. Matthews & L. F. Belucio. 1990.
masses collected in the field had polychaete tubes at- Notas sobre a anatomia, sistematica e biologia de Pugilina
morio (Linnaeus, 1758) (Mollusca: Gastropoda). Arquivos
tached.
de Ciencias do Mar 28:3-8.
The oviposition ofeggcapsules lastedforabout 8 days;
Natarajan, A. V. 1958. Studies on the egg mass and larval de-
females did not eat until spawning was completed. Com- velopment of some prosobranchs from the Gulf of Mannar
munal spawning was not observed in the laboratory. and the Park Bay. Proceedings of Indian Academy of Sci-
ence 46:170-228.
Discussion Rios, E. C. 1994. Seashells ofBrazil. EditoradaFunda^aoUniv-
ersidade do Rio Grande: Rio Grande. 492 pp.
The spawning season ofPugilina morio in the estuary of Robertson, R. 1974. Marine prosobranch gastropods: Larval
the Ceara River determined in the present study, July to studies and systematics. Thalassia Jugoslavica 10:213-238.
November, may be related to the occurrence of the dry
season in the region during this time of the year, when
the salinity in the estuary is higher. According to Mat-
thews-Cascon et al. (1990), the time of reproduction of
Pugilina morio at Salinas Beach, Para State in the north Embryonic Development of Crepidula aculeata
of Brazil, was mainly during the months of September (Gmelin, 1791) (Caenogastropoda: Calyptraeidae)
and October. from the Venezuelan Caribbean
Hatching as free veliger larvae has also been reported
in Pugilina cochlidium by Natarajan (1958). Most of the Patricia Miloslavich', Pablo E. Penchaszadeh- and
other members of the family studied (Melongena. Hemi- Ana Karinna Carbonini'
fusus, Busycon, and Busycotypus) have direct develop-
ment (Clench & Turner, 1956; Robertson, 1974; D'Asaro, ' Universidad Simon Bolivar, Depaitamento de Estudios
1997); however, Melongena melongena fromthe southern Ambientales, RO. Box 89000, Caracas 1080, Venezuela,
Caribbean also hatches as a veliger larva (Bandel, 1975). pmilos(3>usb.ve
We did not observe nurse eggs inside the egg capsules, ^ Laboratorio de Invertebrados, Departamento de
and Clench & Turner (1956) observed the same thing for Biologia, Facultad de Ciencias Exactas y Naturales,
Melongena corona. D'Asaro (1997) estimated the pres- Universidad de Buenos Aires, Argentina
ence of52 to 74 eggs per capsule in Pugilina morio from
Sierra Leone, west Africa, whereas in the present study Introduction
we found a wider range of 50 to 167 eggs per capsule.
The same author compared the egg capsules of popu- The genus Crepidula Lamarck, 1799, is widely distrib-
lations ofPugilina morio from Sierra Leone, west Africa uted in South and North America, with about 20 species
and from Gambia, west Africa and Brazil and found that in the Pacific and Atlantic coast of North America (Ab-
in the first population the exit aperture is located in the bott, 1974; Hoagland, 1986), at least seven species in the
middle ofthe upper side ofthe capsule and in the second Caribbean (Diaz & Puyana, 1994; De Jong & Coomans,
and third population (Gambia and Brazil), the exit aper- 1988; Warmke & Abbott, 1961), and at least five species
ture is displaced laterally, which is consistent with our
own observations.
Acknowledgments. Wethank Dr. PauloGascon forhelpfulcom-
mentsonthe manuscript, AlyssonMarciel Freireforthediagram,
and Tito Lotufo and Carlos Augusto Oliveira de Meirelles for
the photography. For assistance with electron microscopy we
thank Daercio da Costa Magalhaes.
Literature Cited
Bandel, C. 1975. Das embryonalgehause karibischer meso und
neogastropoden (Mollusca). Akademie der Wissensschaften
und der Literatur, Mainz 1:1-133.
Clench, W. J. & R. D. Turner. 1956. The family Melongenidae
in the western Atlantic. Johnsonia 3:161-188.
D'AsARO, C. 1997. Gunnar Thorson's world-wide collection of
prosobranch egg capsules: Melongenidae. Ophelia 46:83-
125.
Matthews, H. R. 1967. Notas sobre a especie Pugilina morio
(Linnaeus, 1758) no nordeste brasileiro. Arquivos da Esta-
gao de Biologia Marinha Universidade Federal do Ceara 7: Figure 1. Dorsal and ventral view of the adult shell of Crepi-
191-192. dula aculeata.